This application is a continuation-in-part of U.S. Ser. No. 055,084, filed May 28, 1987 now abandoned.
Emulsion polymerization of ethylenically unsaturated monomers requires the use of an emulsifier. Conventional anionic, cationic or nonionic surfactants are water-soluble and therefore, decrease the water-resistance and weatherability of films formed from polymer emulsions containing these surfactants. For this reason, it is desirable to use for such purposes a polymeric emulsifier capable of forming a film, or a compound or resin having an ethylenically unsaturated group capable of copolymerizing with monomers to be polymerized.
Japanese Patent Kokai Nos. 54/92917, 54/92918 and 55/51050, assigned to the assignee of this application disclose compounds having an amphoionic group of the formula: ##STR2## wherein R is alkylene or phenylene and Y is --COOH or --SO.sub.3 H, and a radically polymerizable unsaturated group which are useful as a dispersing stabilizer in the emulsion polymerization of monomers.
Japanese Patent Application No. 57/13054 discloses resins having the above amphoionic group and a radically polymerizable unsaturated group which may be used for the same purposes.
The basic concept of these proposals is to prevent bleeding or leaching of emulsifiers from films made of resultant polymer emulsions by introducing a polymerizable function into a water-soluble emulsifier and chemically binding the emulsifier to the resultant emulsion resins. These emulsifiers are, however, still hydrophilic and water-retentive in nature and thus the problem of low water-resistance and weatherability of resultant polymer films remains unsolved by the use of these polymerizable emulsifiers although they are not leachable or bleedable.